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PALEOZOIC CORAL REEFS 245 



phyllum in Wisconsin, Indiana, Ohio, Illinois, Kentucky, western Ten- 

 nessee, Iowa, and British Cokimbia ; in the Cayugan, reefs are locally 

 formed by Stromatoporoids, Favosites, and Hahjdtes in New York and in 

 the Appalachian Valley in Pennsylvania, Maryland, Virginia, and Ten- 

 nessee. 



Europe. — Silurian reefs are reported in the Bala, upper Llandovery, 

 and Wenlock groups of Great Britain, and in Norway, Gotland, the 

 Baltic provinces of Eussia, and Bohemia. 



DEVONIAN 



North America. — The Helderberg group contains reefs composed of 

 Stromatoporoids, Favosites, Halysites, and a few Rugosa in New York, 

 in the Appalachian Valley in Pennsylvania, Maryland, Virginia, West 

 Virginia, eastern Tennessee, and Oklahoma; the Onondaga, reefs of 

 Stromatoporoids, Favosites, MicJielin.ia, Cyatho phyllum, Zaphrentis, 

 Phillipsastrcea, Acervularia, Cystiphyllum, etcetera, at the southern end 

 of Hudson Bay, in New York, Pennsylvania, Virginia, Indiana, Ken- 

 tucky, and Minnesota; the Hamilton, reefs of Stromatoporoids, Favo- 

 sites, Michelinia, and Cyathophylloids and other Eugosa in Ontario, New 

 York, and Michigan. The upper Devonian reefs are composed of 

 Stromatoporoids, Michelinia, and Pachy phyllum (the earlier rugose 

 t}q)es of corals have become rare) in Iowa, Missouri, and Illinois. 



Europe. — Devonian coral reefs are found in Devon, Boulogne sur Mer, 

 Eifel, Ardennes, Belgium, Cologne, Elbingerode in the Harz, and the 

 Karnish Alps. 



CARBONIFEROUS 



North America. — There are no known reefs, properly speaking, in the 

 Mississippian. In the Tennesseean, reefs composed of Michelinia, 

 Lonsdaleia, Lithostrotion, Zaphrentis, etcetera, occur in Indiana, south- 

 ern Illinois, Kentucky, Tennessee, and Alabama; in the Pennsylvanian, 

 Chcetetes and the rugose Campophyllum form reefs in the region from 

 Texas to Kansas, and sporadically elsewhere. 



Europe. — The carboniferous limestones of Ireland, Scotland, Bel- 

 gium, and central Eussia contain reefs composed of Eugosa, Zaphrentis, 

 Amplexus, Diphy phyllum, Clisio phyllum, Lithostrotion, Strephodes, and 

 Columnaria; also Favosites, Syringopora, and Chcetetes. 



A review of the reef-forming Coelenterata of the Paleozoic formations 

 shows that beginning with the Ozarkian group of the Cambrian the 

 same large groups that are at present active reef-builders were then 

 abundantly represented. 



The Archceocyathince of the lower Cambrian were simple corals, and, 

 although sufficiently abundant to form beds predominantly composed of 



